THE DRAMATIC RESULTS OF VAX-D NON-SURGICAL DISC DECOMPRESSION

PEER REVIEWED STUDIES PUBLISHED IN MEDICAL JOURNALS

JOURNAL OF ORTHOPAEDIC & SPORTS PHYSICAL THERAPY (Volume 35 Number 1, January 2005)
SHORT AND LONG TERM OUTCOMES FOLLOWING TREATMENT WITH THE VAX-D PROTOCOL FOR PATIENTS WITH CHRONIC, ACTIVITY LIMITING LOW BACK PAIN
University South Carolina, Columbia, SC; Lebanon Valley College, Lancaster, PA; Virginia Commonwealth University, Richmond, VA
OUTCOME: Significant improvements in a sample of patients with unfavorable prognosis due to chronic low back pain.

JOURNAL OF NEUROLOGICAL RESEARCH (Volume 26 April, 2004)
EFFICACY OF VERTEBRAL AXIAL DECOMPRESSION ON CHRONIC LOW BACK PAIN
Dr. Gustavo Ramos, Valley Neurological Center, McAllen , Texas
OUTCOME: This 144 patient study showed 76% achieved remission of pain. VAX-D should be used in all patients before surgery is undertaken, except in emergent conditions.

ANESTHESIOLOGY NEWS, (March 2003)
A FOUR YEAR FOLLOW-UP STUDY
Robert H. Odell, MD, Ph. D, Daniel A. Boudreau, D.O.
OUTCOME: Four year follow-up after VAX-D treatment shows a sustained 86% reduction in pain and that 91% of patients had resumed their normal activities.

JOURNAL OF NEUROSURGERY (VOL 81: 350-353, 1994)
EFFECTS OF VERTEBRAL AXIAL DECOMPRESSION ON INTRADISCAL PRESSURE
University of Texas, San Antonio, Texas
OUTCOME: Proof that VAX-D actually creates a negative intradiscal pressure force up to negative 160 mm of mercury.

NEUROLOGICAL RESEARCH JOURNAL (October 2001,Volume 23, Page 706 to 714)
DERMATOMAL SOMATOSENSORY EVOKED POTENTIAL DEMONSTRATION OF NERVE ROOT DECOMPRESSION
AFTER VAX-D THERAPY
William K. Naguszewski M.D. Robert K. Naguszewski M.D. ,Coosa Medical Group, Earl E Gose Ph.D.
Dept. of Neurology, Dept. of Bioengineering, University of Illinois
OUTCOME: Pain reduction in the study group was 77% with successful decompression of the nerve roots at multiple levels.

NEUROLOGICAL RESEARCH JOURNAL (October 2001, Volume 23, Page 780 to 784)
A PROSPECTIVE RANDOMIZED CONTROLLED STUDY OF VAX-D AND TENS FOR THE TREATMENT OF CHRONIC LOW BACK PAIN
Department of Orthopedics, Sydney University, Eugene Sherry M.D., FRACS, Peter Kitchener M.B. B.S. FRANZCR , Russel Smart M.B. Ch.B.
OUTCOME: A statistically significant reduction in pain and improvement in functional outcome was obtained in patients with chronic low back pain treated with VAX-D.

CANADIAN JOURNAL OF CLINICAL MEDICINE (VOL 6 NO.1, JANUARY,1999)
THE EFFECTS OF VERTEBRAL AXIAL DECOMPRESSION ON SENSORY
NERVE DYSFUNCTION IN PATIENTS WITH LOW BACK PAIN AND RADICULOPATHY by Tilaro & MIscovich
OUTCOME: VAX-D is significantly capable of influencing sensory
nerve dysfunction associated with a compressive radiculopathy.
Complete remission was achieved by 64% of the study group.

CANADIAN JOURNAL OF CLINICAL MEDICINE (VOL 5 NUMBER 1, 1998)
AN OVERVIEW OF VERTEBRAL AXIAL DECOMPRESSION by Frank Tilaro, MD
OUTCOME: The average pain reduction was 77%.

JOURNAL OF NEUROLOGICAL RESEARCH (Volume 20 , April 1998)
VERTEBRAL AXIAL DECOMPRESSION THERAPY FOR PAIN ASSOCIATED WITH HERNIATED OR DEGENERATIVE DISCS
OR FACET SYNDROME: AN OUTCOME STUDY OF 778 CASES
OUTCOME: The authors consider VAX-D to be a primary modality
for low back pain for lumbar herniation at single and multiple levels, degenerative disc disease and facet arthropathy, and decreased spine mobility .

 

 

ORIGINAL ARTICLE
Outcomes After a Prone Lumbar Traction Protocol for
Patients With Activity-Limiting Low Back Pain: A Prospective
Case Series Study
Paul F. Beattie, PhD, PT, OCS, Roger M. Nelson, PhD, PT, Lori A. Michener, PhD, PT, ATC, SCS,
Joseph Cammarata, DC, Jonathan Donley, DPT

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ABSTRACT. Beattie PF, Nelson RM, Michener LA, Cammarata J, Donley J. Outcomes after a prone lumbar traction protocol for patients with activity-limiting low back pain: a prospective, case series study. Arch Phys Med Rehabil 2008; 89:269-74.

Objective: To determine outcomes after administration of a prone lumbar traction protocol.
Design: Prospective, longitudinal, case series.
Setting: Suburban, chiropractic practice.
Participants: A total of 296 subjects with low back pain (LBP) and evidence of a degenerative and/or herniated intervertebral disk at 1 or more levels of the lumbar spine. We excluded patients involved in litigation and those receiving workers’ compensation.
Intervention: An 8-week course of prone lumbar traction, using the vertebral axial decompression (VAX-D) system, consisting of five 30-minute sessions a week for 4 weeks, followed by one 30-minute session a week for 4 additional weeks.
Main Outcome Measures: The numeric pain rating scale and the Roland-Morris Disability Questionnaire (RMDQ) were completed at preintervention, discharge (within 2 weeks of the last visit), and at 30 days and 180 days after discharge. Intention-to-treat strategies were used to account for those subjects lost to follow-up.
Results: A total of 250 (84.4%) subjects completed the treatment protocol. On the 30-day follow-up, 247 (83.4%)
subjects were available; on the 180-day follow-up, data were available for 241 (81.4%) subjects. We noted significant improvements for all postintervention outcome scores when compared with preintervention scores (P<.01).
Conclusions: Traction applied in the prone position using the VAX-D for 8 weeks was associated with improvements in pain intensity and RMDQ scores at discharge, and at 30 and 180 days after discharge in a sample of patients with activitylimiting LBP. Causal relationships between these outcomes and the intervention should not be made until further study is performed using randomized comparison groups.
Key Words: Back pain; Decompression; Intervertebral disk; Lumbar region; Rehabilitation; Traction; Treatment outcomes.
© 2008 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

LUMBAR TRACTION IS AMONG the oldest known treatments for low back pain (LBP).1 Described by Hippocrates, lumbar traction in various forms has been used for centuries, and continues to be used in today’s clinical environment.1-7 Recent clinical studies,4,8 systematic reviews of literature,5,7,9-11 and evidence-based guidelines12,13 have concluded that the reponderance of evidence fails to support lumbar traction as an effective treatment for patients with LBP. There is concern, however, that the enormous array of potential treatment parameters,3,6 and the lack of methodologic rigor of previous research,5,7 have made the literature regarding lumbar traction inconclusive.

Recently, a newly developed lumbar traction system, vertebral axial decompression (VAX-D), has been gaining popularity. 14-19 During the traction applied with the VAX-D, the patient is prone, with no thoracic harness, on a table specifically designed to eliminate frictional resistance. The VAX-D system provides distraction forces and rest periods through a pelvic harness while the patient stabilizes himself/herself by holding a hand grip.14 It is the manufacturer’s claim that this technology reduces a patient’s reflex spinal muscle contraction and allows distraction of the vertebrae, causing a subsequent symptom reduction.14,15 The 30-minute treatment cycle applied with the VAX-D is typically administered on an outpatient basis 5 to 6 times a week for a period of approximately 4 weeks, then once a week for 4 weeks, for a total of approximately 8 weeks of treatment.

The current, limited body of evidence addressing VAX-D suggests that prone traction applied with VAX-D may decrease intradiscal pressure during load application16 and that this intervention may be associated with improvements in reports of pain intensity.17-19 These studies suggest promising findings; however, long-term outcomes after VAX-D intervention have not been reported, nor has the relationship between VAX-D intervention and measures of disability. Our goal was to expand on the current body of evidence by measuring outcomes after the application of prone lumbar traction applied with VAX-D in a prospective, longitudinal study using validated outcome measures of pain and disability on a large sample of patients. Favorable outcomes would provide data that would assist in the formation of hypotheses that could be tested with subsequent randomized clinical trials. The purpose of the present study, therefore, was to determine short- and long-term outcomes after administration of prone traction using the VAX-D protocol to a sample of patients with activity-limiting LBP that had been refractory to at least 2 bouts of previous, nonoperative interventions.

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From the Program in Physical Therapy, Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC (Beattie); Expert Clinical Benchmarks LLC, King of Prussia, PA (Nelson) and Department of Physical Therapy, Lebanon Valley College, Annville, PA (Nelson); Department of Physical Therapy, Virginia Commonwealth University—Medical College of Virginia Campus, Richmond, VA (Michener); Non-Surgical Solutions LLC, Narberth, PA (Cammarata); and Department of Internal Medicine, Richland-Palmetto Health, Columbia, SC (Donley).
Presented in part to the Combined Sections of the American Physical Therapy Association, February 26, 2005, Nashville, TN. Supported, in part, by a grant from Independence Blue Cross.
No commercial party having a direct financial interest in the results of the research
supporting this article has or will confer a benefit upon the authors or upon any
organization with which the authors are associated.
Reprint requests to Paul Beattie, PhD, PT, OCS, Program in Physical Therapy,
Dept of Exercise Science, Arnold School of Public Health, University of South
Carolina, Columbia, SC 29208, e-mail: pbeattie@gwm.sc.edu.
0003-9993/08/8902-00072$34.00/0
doi:10.1016/j.apmr.2007.06.778

METHODS

Participants
Subject inclusion criteria are summarized in appendix 1. Subjects were eligible for this study if they were aged 18 to 60 years, and had specified medical insurance overage. Subjects must have reported activity-limiting LBP, with or without the presence of associated lower-extremity pain that had an average intensity greater than 4/10 on an 11-point numeric pain rating scale (NPRS)20,21 during the month prior to admission. In addition, all subjects had to have a score of greater than 6/24 on the 24-point Roland-Morris Disability Questionnaire (RMDQ),22 and have imaging evidence of a degenerative and/or herniated intervertebral disk at a segmental level consistent with current symptoms. All subjects must have reported a lack of favorable outcomes after at least 2 previous, nonoperative interventions (eg, joint manipulation, transcutaneous electric nerve stimulation, or oral medication) for their current symptoms (see appendix 1).

We excluded subjects who were currently involved in a workers’ compensation claim, were involved in legal action regarding their back pain, or were on, or applying for, permanent disability related to their low back problem. Additional exclusion criteria included previous treatment with supine or prone applied lumbar traction, activity-limiting pain in areas other than low back and legs, a history of lumbar surgery, current pregnancy, or the use of prescription anticoagulants, corticosteroids, or opiate-based pain medication. Subjects were also excluded if there were radiographic or physical examination evidence of conditions that would represent precautions or contraindications for prone traction applied with VAX-D.These are listed in appendix 2.

We recruited subjects by local newspaper and radio advertisements, and by referral from local health care practitioners. Patient screening and intervention was performed at 2 health care facilities in the greater Philadelphia area between October 2002 and January 2005. All subjects signed a consent form approved by MedRisk’s Human Subject Review Board.

Outcome Measures
Pain intensity. Highest, average, and lowest pain intensity on a typical day were assessed by using an 11-point NPRS.20,21 Anchor points were defined as 0 (none) and 10 (worst imaginable).Previous research has shown measures obtained by this technique to be reliable and sensitive to meaningful change when repeated measures exceed +-2.0.23,24

Roland-Morris Disability Questionnaire. Back-pain–related activity limitation was assessed by using the 24-point RMDQ.22 We determined the RMDQ score based on the frequency of items that were checked by the patient; the scores ranged from 0 (no back pain–related activity limitation) to 24 (severe back pain-related activity limitation). Measures obtained from the RMDQ have been shown to have reliability and content validity, and reflect meaningful clinical change when repeated measures exceed +-4/24.22,25-27

Procedure
Subject screening and intake measures. Prior to admission to the study, potential subjects watched a videotape developed by the manufacturer that described the VAX-D traction. Next, subjects underwent a screening procedure performed to verify the entry and exclusion criteria. If no recent magnetic resonance imaging or computed tomography examination was available, it was obtained prior to admission in the study and was evaluated by a radiologist. Subjects who met the entry and exclusion criteria, and provided written informed consent, were enrolled in the study. At this time, the subjects completed an intake form that contained demographic information and the outcome measures. Each subject was scheduled for daily (5d/wk) prone traction of 30 minutes each for 4 weeks, then once a week for 4 weeks. The entire protocol consisted of 24 visits over 8 weeks.

exclusion criteria, and provided written informed consent, were enrolled in the study. At this time, the subjects completed an intake form that contained demographic information and the outcome measures. Each subject was scheduled for daily (5d/ wk) prone traction of 30 minutes each for 4 weeks, then once a week for 4 weeks. The entire protocol consisted of 24 visits over 8 weeks.

Administration of the prone traction. The treating clinician attached a pelvic harness and positioned the patient prone on the VAX-D table.a The clinician attached an anchor strap to the table and used it to pull the pelvic harness until tension on the digital readout was between 4.5 to 5.4kg, per the VAX-D protocol. The hand grips were adjusted to accommodate the subject. The pulling force on the pelvic harness applied traction as the patient stabilized himself/herself via the handgrips. The relaxation and distraction times were set at 60 seconds each, with the cycle counter set at 15 cycles. The working pressure was then adjusted to the desired level. The working pressure was typically between 8.9 and 9.8kg/cm2, and was based on patient comfort. After the 30-minute treatment, the subject was instructed to roll onto his/her side and sit on the side of the table for approximately 1 minute prior to leaving the facility.

Follow-up measures. We obtained outcome measures at the time of the last treatment visit (discharge), which was 8 weeks after the start of intervention. Additional measures were obtained at 30 days postdischarge, and at 180 days postdischarge. The treating clinicians were blinded to these measures. The original protocol called for all patients to provide follow-up measures in person at 30 and 180 days after discharge. However, because of poor compliance with this process, the protocol was modified to allow patient follow-up measures to be completed by telephone when subjects failed to appear for follow-up visits. Despite this effort, 18.6% of subjects did not provide follow-up data at 180 days. We monitored protocol and documentation compliance by having an independent blinded clinician perform audits of the 2 facilities performing the study. This process was carried out in the first 6 months of the project. Within that 6-month period, the auditor reported that the protocol for patient data collection and intervention was carried out appropriately by the providers. After the 6-month period, the auditor would appear at clinics, unannounced, each month to perform a complete audit of cases.

Data Analysis
We mailed the study’s intake and follow-up data sheets to a research assistant who coded and entered all data. To account for those subjects lost to follow-up, the preintervention scores were used as follow-up measures, thus conservatively assuming no change from preintervention status (intention-to-treat [ITT] strategy).28,29 Demographic data and outcome measures were summarized. A single-factor, general linear model, repeated-measures analysis of variance was used to determine differences in each of the outcome measures over time. Mean differences from preintervention scores and 95% confidence intervals (CIs) were computed for each of the outcome measures for discharge, 30 days postdischarge, and 180 days postdischarge.

Because of the repeated-measures design, a Bonferroni correction was made to the CIs to reduce the likelihood of
type I statistical error. Effect size differences were quantified by using the d-index described by Ottenbacher and Barrett30 where:

A small effect size is d less than .50; medium effect size is dranging between .50 and .79; and large effect size is d greater than .80. All analyses were performed with SPSS.

RESULTS
Subject Characteristics
A total of 303 subjects enrolled in the study between October 2002 and January 2005. Six subjects were not included in this analysis because of incomplete initial data. One additional subject was not included because of failure to meet an inclusion criterion (RMDQ admission score, <6/24). From the sample of 296 subjects used for this analysis, 203 were men, 85 were women, and 8 did not indicate sex. Subjects’ mean age +- standard deviation (SD) was 44.2+-9.2 years. The majority of subjects (n=234 [79%]) reported that their presenting symptoms of LBP were present for greater than 6 months. Of the remaining subjects, 25 (8.5%) reported symptoms of less than 2 months, and 29 (9.8%) had symptoms of between 2 and 6 months in duration. Subject characteristics are summarized in table 1.
The majority of the 296 subjects (n250 [84.5%]) received 16 to 24 treatment visits of prone traction. Because of difficulties with transportation and bad weather, not all subjects received the full 24 visits. Of the subjects who completed the protocol, 247 (83.4%) provided follow-up data at 30 days postdischarge and 241 (81.4%) provided follow-up data at 180 days postdischarge. There were no adverse events reported during the course of the study.
Numeric pain rating scale. The mean preintervention measures of lowest, average, and highest pain intensity on a typical day are depicted in table 2. When ITT strategies were used, significant improvements were noted for all follow-up measures of pain intensity compared with the preintervention measures (P
.01) (see table 2). Highest pain intensity was significantly lower at 180 days follow-up than at discharge (P
.01). There were no significant differences between the other follow- up measurement points for pain intensity. The mean decreases in pain intensity from the preintervention scores ranged from 1.6 (lowest pain at discharge) to 2.8 (highest pain at 180 days follow-up) on the 0 to 10 NPRS. Effect size reductions in pain intensity were high, ranging from 1.6 (lowest pain at 30 days follow-up) to 2.0 (highest pain at 180 days followup, and average pain at 30 days follow-up) (see table 2). The lower boundary of 95% CI was greater than the proposed minimal detectable change score of 2.023,24 for all follow-up measures of highest pain intensity, and for 30 days and 180 days follow-up measures of average pain intensity when compared with preintervention scores.
Roland-Morris Disability Questionnaire. The mean preintervention measure  SD of the RMDQ was 12.64.8 (range,
0 [normal] to 24 [worst possible score]). Significant improvements were noted for all follow-up measures compared with the preintervention score (P
.01). The mean RMDQ score at 180 days follow-up was significantly improved compared with discharge (P
.01). Mean change in the RMDQ scores compared with preintervention were 5.6 at discharge, 6.6 at 30 days postdischarge, and 6.7 at 180 days postdischarge. In all cases, the lower boundary of the 95% CI indicated a reduction of 4.0 or more points, suggesting the likelihood of clinically detectable change (see table 2).26,27 The effect sizes ranged from 2.0 to 2.3 for the 3 follow-up measures compared with preintervention scores (see table 2).

DISCUSSION
This prospective, longitudinal case series provides preliminary information describing outcomes after prone traction with VAX-D. Patients reported significantly improved pain and RMDQ scores after 16 to 24 visits of prone traction at discharge, and at 30 days and 180 days postdischarge. However, there was large variation in the magnitude and meaningfulness of the degree of change in these measures. We noted large effect size differences for highest and average pain intensity, and for the RMDQ scores at all follow-up measures (see table 2). The lower boundary of the 95% CI was greater than the minimal detectable change score for highest pain intensity23,24 and the RMDQ score26,27 at each follow-up measure and for average pain intensity at 180 days postdischarge, indicating the likelihood that these measures reflected clinically detectable improvement. The effect size differences for lowest pain intensity
were also large; however, the lower boundary of the 95% CI was less than the minimal detectable change at each follow-up measure. Therefore, there is uncertainty regarding the meaningfulness of the degrees of improvement that occurred with the lowest pain intensity.

Prone traction applied with the VAX-D has the advantage of being noninvasive with a relatively low risk of injury to the patient. Although Deen et al31 described an occurrence of acute intervertebral disk protrusion associated with this form of traction, we were unable to locate other reports of adverse events. One limitation of the VAX-D, however, is that it is more expensive to administer than most conventional traction protocols. The manufacturer justifies this cost as based, in part, on the presence of the VAX-D’s automated “logic-control mechanism” that is purported to provide a unique type of traction pull not available in less expensive, conventional traction devices.14,15

Arguments can be made that if outcomes after prone traction using the VAX-D are superior to those after conventional traction or other equivalent interventions, investing in and reimbursing for traction provided by the VAX-D system may be cost-effective. Further study is necessary to substantiate this. It is important to note that the traction applied via VAX-D also differs from most conventional lumbar traction in a variety of ways; the subject is positioned prone on a low-friction surface as opposed to supine on a high-friction surface; a pelvic harness is used as opposed to a thoracic harness; and the protocol indicates a high frequency of treatments over a 2-month period.

Thus, it is unknown to what degree subject positioning, surface, type of stabilizing harness, and treatment dosage, rather than the unique traction pull of the VAX-D, contribute to the outcomes after intervention. We were unable to locate any studies that provided direct comparison of outcomes of traction via VAX-D compared with less expensive forms of conventional lumbar traction.

Our preliminary results suggest a generally favorable association between the prone traction applied with the VAX-D and the outcome measures used in this study; however, because we lacked a randomized control group, we cannot imply a causal relationship between the traction applied with VAX-D and outcome. For example, although we chose a sample that potentially had an unfavorable prognosis for recovery, ie, a history of previous failed treatment,32 we cannot determine the degree to which the natural history of a subject’s condition influenced outcome. We also cannot determine the degree to which changes in outcome measures were related to biologic effects resulting from the VAX-D versus a placebo effect.33 All subjects had preintervention imaging evidence of lumbar intervertebral disk degeneration and/or herniation; however, the degree to which these findings were associated with symptoms, 34-36 or were influenced by the treatment, is not known. Further study is needed using randomized control groups and intervertebral disk imaging before and after intervention.

Study Limitations
Several limitations must be addressed in this study. It is also important to note that our findings can be generalized only to a sample of patients with activity-limiting LBP. We did not classify subjects based on the presence or absence of spinal nerve compression. None of our subjects were on permanent disability due to back pain, were receiving workers’ compensation, or were involved in litigation. Subjects were included in this intervention trial only if they lacked favorable outcomes after at least 2 previous nonoperative treatments for their LBP. Our sample was primarily composed of middle-aged adults who were currently working and reported moderate to high preintervention pain intensity (range, 3.9–7.3) and moderate pain-related activity limitation (mean RMDQ score, 12.6). Most subjects had symptoms of greater than 6 months in duration, were nonsmokers, tended to be overweight or obese, and did not exercise regularly. It is not known if prone traction applied with the VAX-D would be associated with similar findings in patients who have different characteristics from our sample.

CONCLUSIONS
Prone traction delivered with VAX-D for 16 to 24 visits was associated with significant improvements in pain intensity and RMDQ scores in both short-and long-term follow-up, in patients with activity-limited LBP who had previously failed 2 nonoperative interventions for their current symptoms. Causal relationships between the outcomes and the intervention cannot be made. Further study is needed using randomized comparison groups.

Acknowledgments: We acknowledge the following people for valuable assistance in this project: John Barbis, MA, PT, OCS, and Joan Nicolazzo. We also thank Claire Coyne for her copyediting services.

The opinions expressed in this study are solely those of the authors; Independence Blue Cross does not endorse any findings from this study.

OUTCOMES AFTER PRONE LUMBAR TRACTION, Beattie

APPENDIX 1: STUDY INCLUSION CRITERIA

Variable	Criterion
Age (y)	18-60
Symptom type and distribution	Pain must be present in low back and may also be present in any of the following areas: 1 or both buttocks, 1 or both thighs, 1 or both legs. Pain must be the primary complaint, although dysesthesias (pins and needles, numbness) or lower-extremity weakness may also be present.
Symptom severity	Average pain of equal to or greater than 4/10 over the last month. The RMDQ score must be at least 6/24.
Diagnosis and medical examination findings for current condition	Must have undergone a medical examination by a primary care physician, rheumatologist, orthopedist, neurosurgeon, or neurologist that has ruled out nonmusculoskeletal causes for the current symptoms. Must have undergone spinal imaging (magnetic resonance imaging, computer tomography scan, diskography or myelography) that confirms the presence of a degenerative and/or herniated lumbar intervertebral disk at a segmental level consistent with the current symptoms.
History of “failed” prior treatment	All subjects must have had persistence of symptoms after a reasonable course of at least 2 prior, nonoperative reatment approaches. These treatments must have been discontinued due to worsening of symptoms or failure of symptoms to substantially improve.*
Abbreviation: RMDQ, Roland-Morris Disability Questionnaire. *Examples include: exercise, massage, joint manipulation, acupuncture, injection therapy (either epidural, facet, or soft tissue), transcutaneous electric nerve stimulation or other form of electrotherapy, a course of pain-relieving oral medications (steroidal, nonsteroidal, opiate), biofeedback, or a lumbar orthosis.

APPENDIX 2: STUDY EXCLUSION CRITERIA

Currently involved in a worker’s compensation claim or personal injury litigation

Currently on, or applying for, permanent disability related to LBP

Previous treatment using lumbar traction or VAXD

Activity-limiting pain arising from any site other than listed in specific entry criteria

A history of a surgical procedure to the lumbar spine

Known or suspected current pregnancy or recently postpartum

Currently taking prescribed anticoagulants (this does not include low doses of aspirin), corticosteroids, and/or opiate-based analgesics

Vertebral osteoporosis, spondylolisthesis or retrolisthesis of greater than 50%, or vertebral fracture with current bony instability or measurable deformity

Severe lumbar stenosis (anteroposterior diameter of the thecal sac of less than 5mm at any level, from mid-sagittal lumbar magnetic resonance imaging)

Inflammatory, infectious, or neoplastic disease involving the spine

Spinal or lower-extremity nerve impairment not resulting from spinal nerve compression in the lumbosacral spine.

Abdominal aortic aneurysm, chronic ileus, inflammatory bowel disease, unstable angina, congestive heart failure, orthopnea, or severe hypertension

Any surgical procedures to the abdomen, thorax, upper extremities, head, or neck in the 6 months prior to enrollment in the study

Any condition involving the cervical-thoracic spine or upper extremity that would be adversely affected by VAX-D. This is defined as an inability to assume and maintain the prone position while “pulling” with both upper extremities, for
example, severe kyphosis, adhesive capsulitis of the shoulder, and weakness of handgrip Open wounds or skin rash on the back

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Suppliers

a. VAX-D Medical Technology LLC, 310 Mears Blvd, Oldsmar, FL 34677.
b. Version 12.0; SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL 60606.

ALL RIGHTS RESERVED MSO LLC COPYRIGHT © 2008. Use by permision only.

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Vertebral Axial Decompression

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a report by
Frank Tilaro
Doctor of Internal Medicine, Utah

Reduction of a nuclear protrusion by spinal distraction was practiSed even before the intervertebral disc was recognised. A 14th-century translation of Albucasis’s Surgery illustrates lumbar manipulation during spinal traction.1 Apollonius of Kitium describes a form of distraction 2,000 years ago. Guidi (1544) illustrates a traction table in his Chirugia, and one of his tables can be found in the Wellcome Historical Museum of London. In their book on manipulation past and present, Cyriax and Schotz2 illustrate the employment of traction by Hippocrates (400 BCE), Galen (131–202 CE) and the Spanish-Arabian physician Abu’L Qasim (1013–1106 CE).

Today, two methods of performing traction are practised: the sustained manner, preferred by Cyriax, and various forms of intermittent traction. Intermittent traction can be performed electronically, manually (by a therapist) or by the patient (autotraction).

The effects of distraction include tautening of the posterior longitudinal ligament, which exerts a centripetal force at the back of the joint.

The effects of sustained traction have been investigated. An increase in body length of 10–30mm was demonstrated in healthy males when a sustained force of 60kg was applied for one hour, and was lost at 4mm/hr.3 In the excised spine the greatest separation was in those subjects with wide disc spaces, and the least in those with evidence of disc degeneration.

Other investigators confirmed an increase in stature over and above that known to occur when the load is taken off the spine by lying down.4 The findings suggest that most of the vertebral separation takes place within the first 30 minutes. During normal traction, the enlargement between two consecutive lumbar end-plates is between 1 and 1.5mm. Other studies have demonstrated a widening of the lumbar intervertebral space of between 3 and 8mm, measured
radiographically during gravitational traction.5,6 Anderson et al.7 have shown an increase in intradiscal pressure with certain traction techniques.

The heavy lumbar paravertebral muscles exert resistance to distraction. At least 30–35kg of force is required to influence the lumbar spine.5 Other studies have shown that a force of at least 25% of bodyweight is necessary to achieve lumbar distraction. With the split table, designed by Dr Allan Dyer, it is estimated that 25% of the traction force is required for distraction to occur.8 The effects of distraction include tautening of the posterior longitudinal ligament, which exerts a centripetal force at the back of the joint. This manoeuvre may be of therapeutic value, particularly if the protrusion is located anterior to and remains in close contact with the ligament. On the basis of biomechanical calculations, significant intradiscal negative pressure may be achieved during sustained traction.9 One study has shown that a traction load of 30kg caused the intradiscal pressure to drop from 30 to 10kp in the L3 intervertebral disc.10 Improvement in nutrition, deposition of reparative collagen and healing of annular tears and fissures have all been suggested as benefits of axial distraction.

Dr Allan Dyer, former Deputy Minister of Health from Ontario, Canada, and a pioneer in the development of the external cardiac defibrillator, designed the vertebral axial decompression (VAX-D) therapeutic table to apply distraction tension to the patient’s lumbar spine without eliciting reflex paravertebral muscle contractions. A patented harness is attached to a tensiometer during separation of the movable part of the table. The distraction–relaxation cycles are automated or variably timed. Distraction tensions and rates are continuously monitored and measured by the tensiometer, and the output is shown on a digital gauge and captured on a pen-write printout.

Procedure
The VAX-D table utilises pneumatic cylinders coupled with hydraulic damping as the drivel-damping mechanism for the pre-tension and therapeutic programme. The technology applies and maintains a baseline tension of 20–24lb (the pre-tension) to the patient’s pelvis throughout the treatment session (even during the rest periods), and the distraction cycles then move from tile-pre-tension range up to a pre-selected therapeutic tension. The above parameters are absolutely
critical to the success of the treatment. The pneumatic hydraulic cylinders separate the lower table section from the upper section and apply the tensions to the patient’s pelvis. The pneumatic hydraulic drive mechanism allows precise control of the amount of tension and is able to apply tensions in a logarithmic time/force curve. The pneumatic hydraulic drive mechanism is applied in both the distraction and retraction movements of the VAX-D table and provides a smooth,
controlled operation with gradual return of the patient to the starting position each time. To achieve optimum control of the application of distractive tensions, it was found essential to develop a harness that would attach directly to an electronic tensiometer, which continuously monitors and provides feedback of the tensions being applied to the spinal column. The harness design also facilitates proper placement, which is necessary to attain reproducible results.

Patients with discogenic low-back pain – with or without radiculopathy – who have failed conventional therapy become candidates for VAX-D therapy after six to eight weeks.11 Patients with neurological deficits are also candidates since outcome studies have shown no difference with surgical or medical management.12 Patients with fusion or failed back
surgery syndrome are also candidates.

Contraindications for VAX-D therapy include infection, neoplasm, osteoporosis, bilateral pars defect, unstable grade 2 spondylolisthesis, fractures and the presence of surgical hardware in the spine.11 The patient should be evaluated by a therapist or physician prior to initiating therapy, and routine spine films are necessary to rule out any contraindications. A computed tomography (CT) or magnetic resonance imaging (MRI) scan is not a pre-requisite before therapy, but most patients have undergone neuroimaging. A trained VAX-D technician administers the daily therapy for approximately 20 sessions. An occasional patient may require a short maintenance period in which two to three treatments a week are given for two to four weeks following initial therapy. The average patient has required 20–25 sessions. Each session is 15 cycles, each cycle being one minute in distraction and one minute in relaxation.

Patients are instructed to wear loose clothing for each treatment. The patient is placed prone on the table so that the superior border of the pelvic harness is at the level of the split. The patient then grasps the adjustable handgrips, which are positioned to ensure the arms remain straight without bending the elbows. A roll is placed under the patient’s ankles – a chin or forehead roll is optional. Patients who have difficulty lying prone can use a pillow placed under the abdomen.
Patients with shoulder pathology may employ a roll under the axilla. The patients are instructed to hold tightly to the handgrips, since

Patients with discogenic low-back pain – with or without radiculopathy – who have failed conventional therapy become candidates for vertebral axial decompression therapy after six to eight weeks.

motion artifact can be seen on the graph printout if the patients are pulling with their arms. This manoeuvre inhibits decompression. Patients are allowed to release their grip during the relaxation phase. A pre-tension level of 20lb is set and maintained throughout the resting phase. Ramos13 demonstrated that 50lb of tension was the threshold tension necessary to develop negative intradiscal pressures. Women start with 50Ib and work up to 70lb. Men usually start at 60lb and work up to 80lb. Tension increments are in the order of 5lb every three to four days, although some patients need to proceed more slowly. Tension should remain constant for each treatment cycle (see Figure 1).

If the centralisation phenomenon – the movement of pain pattern from a distal to a more proximal location – occurs in the early treatment stages, the patient will most likely respond to physical therapy and not require further VAX-D. Centralisation may appear at a later stage of treatment or shortly after completing a full VAX-D course. In patients with an intact annulus, no researcher has yet reported on the results of CT discography prior to treatment and following the onset of centralisation.14 Pain during distraction that lessens with relaxation is probably due to stretching shortened tissue. If pain persists for more than 30 minutes after treatment, the tension should be reduced for the next few
sessions. The tension should be lowered or the treatment cycle stopped for pain that increases with each two-minute cycle. Some patients require a two- to three-day hiatus from therapy if they have too much discomfort. The daily response to treatment and any changes made are recorded in the patient’s chart and reviewed by the physician and
technician every few days.

Patients are encouraged to remain active, but should not engage in strenuous activities while undergoing therapy. They should not be receiving any other treatment modalities while receiving VAX-D therapy. Patients may wear a back support after therapy, but it should be removed within one to two hours. Once the VAX-D course is completed, patients are encouraged to enter some form of rehabilitation programme and learn proper biomechanics.

Discussion
Ramos and Mart13 studied intradiscal pressures during VAX-D treatment. Five cases with subligamentous disc herniation at L4–5 – confirmed by MRI and scheduled for percutaneous discectomy – were chosen. Using lateral and anteroposterior (AP) fluoroscopy, a cannula was inserted into the nucleus pulposus of the L4–5 intervertebral disc.The pressure measurements were recorded by an Ohmeda pressure transducer connected to a Hewlett-Packard pressure monitor via a
saline bridge and a Camino fibre optic intracranial transducer, adapted for intradiscal measurements. Since the pressure transducers were designed to measure changes in the positive range, calibration was necessary. The pressure transducer and monitor for each patient were individually calibrated, and a correction curve was plotted showing the transducer readings versus actual pressures to correct for the non-linearity of the instrumentation in the range of the negative
pressures achieved. A pneumatic calibration analyser was employed. Distraction tensions ranging from 50 to 100lb were monitored on a digital read-out and recorded on a continuous graph tracing by a chart printer incorporated in the control console. Intradiscal pressure changes were observed as a digital read-out on the pressure monitor. Intradiscal

Although compression is a frequent finding in sciatica, compression does not explain all the observed symptomatology.

pressures were significantly reduced to negative levels, ranging from a negative 100mmHg to a negative 160mmHg. Changes in intradiscal pressure were minimal until a threshold distraction tension was reached. The relationship between percentage maximum tension and time was a logarithmic function. If one plots the percentage of the maximum tension reached in 60 seconds versus time, it takes 17–20 seconds to reach 50%, 25–28 seconds to reach 70% and 42–45 seconds to attain 90% of the maximum. The retraction phase followed a linear time– tension relationship and returned to baseline in 25–30 seconds.

The first large-scale retrospective study15 involved over 700 patients with low-back pain – with and without radicular symptoms. Over 70% achieved a positive outcome. Even though the study was not a randomised blinded trial, the majority of patients were suffering beyond the period where natural resolution would be expected. All had failed treatment with other modalities and demonstrated a positive response during treatment and/or immediately thereafter.

Sherry et al.16 conducted a prospective, randomised controlled trial of VAX-D versus transcutaneous electrical neural stimulation (TENS). All patients had chronic symptoms (with the average duration of pain being 7.3 years). TENS was regarded as a placebo. The data revealed an attributable success rate of 68.4% for VAX-D, significantly superior
compared with TENS (p<0.001).

A study by Ramos13 compared the effects of a subtherapeutic treatment versus the protocol treatment. All patients had symptoms of sciatica and were referred to a neurosurgeon after failing conventional therapy. Imaging studies and the clinical examination were concordant. The protocol group showed significantly superior results compared with the subtherapeutic treatment group. Two similar studies evaluating the effect of VAX-D on sensory nerve dysfunction in cases of low-back pain came to similar conclusions.17,18 Either a current perception threshold neurometer or dermatomal somatosensory-evoked potentials protocol was employed. Both studies demonstrated that VAX-D was capable of positively influencing sensory nerve dysfunction associated with compressive radiculopathy. Although compression is a frequent finding in sciatica, compression does not explain all the observed symptomatology. Other factors include the
force and rapidity of compression, the effect on arterial and venous circulation and the release of pain, vascular and neural modulators – nitrous oxide, phospholipase A2, the prostaglandins and leukotrienes.19–22

Summary
VAX-D should not be considered as traction in the traditional sense, but as decompression: it is the only non-invasive treatment that has been proved to decompress only the disc. With other traction devices, there has been indirect proof. The patented therapeutic curve demonstrates that, when time is plotted against force, one observes a logarithmic

Vertebral axial decompression should not be considered as traction in the traditional sense, but as decompression: it is the only noninvasive treatment that has been proved to decompress only the disc.

function. Conventional traction devices have a linear time–force relationship. Non-steroidal anti-inflammatory drugs, steroids and doxycycline have been given in conjunction with VAX-D therapy to study possible diffusion into the disc and any beneficial effects. Other concepts for the future include investigation of immunomodulators, transplanting live fibroblast and chondrocytes and minimally invasive surgical techniques in conjunction with VAX-D. The current focus may shift from treating back pain to repair and healing of the damaged disc.

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